The car did have fabspeed headers on it before I had them swap to stock. Do headers make any difference at this level? I assume not? In other words, having headers with OEM cats and Sharkwerks exhaust won't be enough for stage 2 right? Since cats are the constraint. I don't know how long the car ran with stage 2 map.

 

The stock headers are not the issue with backpressure, they are upstream of the turbos and by most accounts a pretty decent design. Sharkwerks claims they have not found any measurable performance improvement on our cars from aftermarket headers. Cobb doesn't recommend the headers be replaced for stage 2, just from the cats back. That being said the Fabspeed headers are another nice gift assuming a local shop can touch up the cracks.

Edit: I suspect the previous owner had a cat bypass (or maybe aftermarket cats) and put them back in to sell the car, perhaps at the dealer's insistence if he traded it in. Why spend all that money and leave the bottleneck in? The Cobb AP with PDK is $2.5k, Fabspeed headers is $1.6k, Sharkwerks muffler bypass is $1.6k, IPD plenum is $1k so we are talking nearly seven grand. Cat bypass is only another $800.

 

Spoke to the previous owner..was able to get hold of him. Never had a cat bypass or high flow cats. The dealer he worked with on the cobb said that Stage 2 with this set up is not really a big issue apparently. So he was running Stage 2 with this set up.

 

Serious issues like knock/detonation due to back pressure which equates to higher exhaust/cylinder temperatures. This is why you can run more boost and more aggressive timing with less restrictive exhausts, cats/test pipes.

 

I saw the data logs that were run before...not showing any knock....anyway I took it down to Stage 0 for now

 

I’d bin the fabspeed headers (you mentioned they had cracked?) - have multiple friends who had their headers and exhausts crack, and plenty of feedback on these forums 5-6 years ago of shoddy craftsmanship. Stock headers are fine by all accounts. You would notice after market cats as you can feel it spoil quicker, and it sounds better

 

Yes...hairline crack on the fabspeeds

 

Did the Cobb pdk relearn and it seemed to make difference in terms of smoothening out the shifts

 

GT2 and GT2RS come with 600cel cats from
the factory and are ‘tuned’ TT’s so I wouldn’t worry too much.

 

Have the Speedtech 3" Exhaust with 200 Cell Cats and muffler delete. (sounds great)
Cobb Stage 2 Tune for 93 octane. Performance is superb. Also have PDK Cobb Tune which definately makes shifts more agressive
Only problem Turbo Diverter Valves could not handle the extra boost and would make chirping noise under full boost as valve would open.
Replaced with Forge Turbo Diverter Valves which have selectable spring replacement to match boost ($300.00 for pair) Fixed problem.
According to Cobb should be putting out somewhere in the 600HP range.
Night and Day difference between Standard Tune and Cobb Stage 2.

 

Exactly...Also emailed Sam@ByDesign and Markski...both set my mind at ease.

 

That does sound great! Looks like I have after market DVs as well ...PO does not remember which...he thinks maybe EVOMs. The Sharkwerks muffler delete sounds really good as well...even with stock cats

 

Not surprising but good to know, also great of these guys to weigh in when you aren't (yet at least!) a customer. Like some of us said early in the thread, it probably wouldn't make the full power advertised by Cobb but otherwise not an issue.

Since you are new to 911s just try to enjoy the car and not get too sucked into worrying. The IMS bearing and bore scoring threads over in the 997 forum are filled with anxiety that feeds on itself, with lots of hyperbole and uninformed speculation. Even so, our cars don't have the former and the latter is extremely rare in 997.2 series cars. The NA 9A1 engine and the turbo variant have shown themselves to be very reliable, but some folks just can't help themselves. I wrote the PDK repair sticky thread over in the 997 forum because I got tired of reading over and over that any $30 part failure in the PDK leads to a $20k transmission replacement. It's just not true.

Learn as much as you can but enjoy the car and don't worry too much. Having a 911 turbo is the fulfillment of a dream for many of us, it's supposed to be fun!

 

Thanks...that's the advise my wife gave me as well. Regarding the PDK issue are you talking about the built in temperature sensor? Don't they have a new procedure now to fix it without replacing the entire tranny?

Also I have no issues with the mods on the car (mostly very good stuff) but primarily concerned about the CPO.

Yes Sam, Markski and Cobb were super responsive to my questions (they really didn't need to be). Cobb especially spent time with me on the phone talking me through the process when I thought the ECU was bricked.

 

Porsche considers the PDK not serviceable aside from a few exceptions like the temp sensor. Porsche's own t-shooting flow diagrams end up at "replace PDK transmission" for things as mundane as gear oil leaking from a seal. For things like the temp sensor replacement the dealerships charge over $3k despite the fact the part is 35 bucks and it takes less than a day's work. Porsche insists the entire valve body be replaced ($3k list price plus at least another grand in labor) when the fault is usually a $50 solenoid. This assumes they can actually track it down to the valve body and don't default to their usual "replace PDK transmission" diagnosis. There are three other sensor types in the PDK that Porsche claims require a transmission replacement in the event of failure. All three are available, ranging from $100 to $900. None are available from Porsche (nor is that $50 solenoid) and they provide zero information on replacement. Turns out the PDK is very repairable, Porsche and the dealerships want to pretend it isn't. Folks who aren't mechanically-inclined take this at face value rather than rightly questioning why every other transmission is repairable and this one supposedly isn't.

The good news is the PDK is very reliable and we know enough about it now to fix the most common failures. However, a few took it in the shorts pretty good over the years and were pretty vocal about it (understandably). This led to a lot of "ticking time bomb" comments.